1. Species interactions are typically
stronger and more specialized in the tropics.

2. Local diversity is declining in
most or all localities

3. Species’
poleward geographic range limits typically are set by abiotic factors, not
species interactions.

Jeremy contacted Dan Bolnick and I and suggested the perhaps
it would be interesting to do a similar poll for evolutionary biology. We agree.
For starters, we would like to get your opinion from the comments section on
this post to select a series of questions for use for the formal poll. As
examples, I am going to here suggest a few questions of the sort and form that would
work well for a survey.

1. To a first approximation, neutral processes
can be ignored as an explanation for organismal trait variation.

2. To a first approximation, neutral processes
can be ignored as an explanation for speciation.

3. Evolutionary constraints are a strong
influence on short term evolution.

4. Evolutionary constraints are strong
influence on long term evolution.

5. Gene flow generally constrains
adaptive evolution.

6. Character displacement is an important force
in trait evolution.

7. Reinforcement is an important force
in speciation.

8. Sympatric speciation is very rare.

Please suggest some more controversial
ideas in the comments below. If you are curious about the survey to come, here
is some text from the Dynamic Ecology poll, modified slightly for the present
context.

Scientific controversies provide a
fascinating window into the collective scientific process. The cartoon
idealized image of science is a rigorous process, conducted by objective
individuals, that converges on the truth. Which makes it mysterious why there
would ever be scientific controversies, as opposed to mere uncertainty due to
lack of evidence.

But for
scientific controversies to give insight into how science actually works, you
have to know which scientific ideas actually are controversial, or to what
extent they’re controversial. That’s not always easy to figure out, even for
scientists themselves! For instance, the scientists who publish on an idea
generally are only a minority of the scientists with an opinion on the idea,
and not a randomly-sampled minority. So you can’t always read the literature
and tell the difference between, say, an idea that splits scientific opinion
down the middle, and an idea on which most scientists believe X but a vocal
minority believe not-X (see here and here for discussion).

Hence
this poll! It will list a number of controversial or possibly-controversial evolutionary
ideas. Readers will then indicate if they think each idea is definitely false
(“1”), definitely true (“5”), or somewhere in between.

Each idea will be
stated briefly, without caveats or elaboration, the way it might be summarized
in a textbook or in the beginning of a paper. That’s the only practical way to
poll on this. Plus, arguably the reason why evolutionary ideas become both
widespread and controversial is by getting stripped of details, nuance, and caveats.

Saturday, April 7, 2018

Editor's note (from Dan Bolnick): The following is a reflection written by Cole Thompson, who was an undergraduate at the University of Texas at Austin and worked in my lab from 2013 until his graduation in 2015. Cole is now a PhD student at the University of Texas. From his work in my lab, he produced a first-authored paper and was a co-author on two other papers.

I arrived on the University of Texas at Austin campus in August 2011 excited by the opportunities that college would provide me. I had chosen UT largely in part because of the excellent science departments. However, as sophomore I was still looking to find my place on campus. On a cool January day walking the halls of one of the building I had class in, I found a poster searching for students interested in doing biological field work in Canada. Excitedly, I sent my resume to Dr. Dan Bolnick. He shot me back an offer to meet him and discuss the summer work—an NSF funded project on the parallel evolution of three-spine stickleback in evolutionarily independent lake-stream pairs on Vancouver Island. At the meeting he offered me the summer position and I accepted, unaware of how great of an impact this would have on my life.

As I learned later during my time in the lab and undergraduate studies, Vancouver Island is an ideal location for examining how parallel evolution has occurred. As most readers of this blog will know, stickleback colonized lakes and streams on Vancouver Island about ~12,000 years ago after the last ice age. The result is many replicate pairs of neighboring lake and stream populations.

Finally, the spring semester ended and we were slated for a May 21, 2013 departure, but I excitedly and mistakenly arrived for departure a day early. The next morning, arriving at the correct time I met Dr. Yoel Stuart, the postdoc running the parallel evolution project, as well as Dr. Travis Ingram, another post-doctoral researcher conducting field work on the assortative mating of stickleback on Vancouver Island. Our trip began with a four day drive from Texas to British Columbia, which showed the beautiful side of the western US, and as we approached British Columbia I disconnected from the grid and my excitement for the summer grew. Once we arrived at our cabin on Roberts Lake, the real work began--sorting through fish traps, labeling tubes for storage of fins and eggs, preparing tea bags to store fish, and learning the codes for assessing the habitat surrounding the trap as part of gathering the ecological data for each fish trap, and, most importantly, dealing with the constant rain.

After a couple of days of preparing materials we went to the first site—Comida Lake. The process, which was to be repeated for 16 lake-stream pairs, began. After bushwhacking to the site, 50 traps to collect the fish were set, recording their GPS coordinates and marking the time placed in the water. Then the depth, trap habitat, and flow rate (if applicable) were measured while a couple members built a processing location where trapped fish could be sacrificed and then weighed, measured, and have their fin clips cut for DNA sequencing. After two hours, the traps were checked with the stickleback taken for processing. This was done until 80 fish had been collected. After all the fish had been collected, the four most productive traps were identified and samples of the substrate and zooplankton tows were taken at each of their location. Then we used a spectrophotometer to measure the amount of down- and side- welling light at water level and one and two meters below the surface. The first site proved that this summer was exactly what I had hoped, and as I stood in the 50 degree water in the pouring rain with my hands barely able to move I was thankful to be doing science.

After a week of working on lakes close to the base camp, we moved to the northern part of the island to begin collecting at a different watershed, heading out to Joe Lake on June 3rd, 2013. In the early afternoon, while transporting fish to the processing station, I impaled the bottom of my foot. A sharp branch edge sliced through the boots of my waders, my sock, and an inch into my foot. Surprised by this, I gingerly finished transporting the fish I was carrying and then calmly sat and irrigated the wound with sterile iodine solution. Luckily most members of the field team had been asked to take a weekend-long wilderness First Aid class before going to Canada, a time investment that paid off. . After initial first aid, we headed to the Port McNeil hospital. The result of the injury was not so bad, just stitches and crutches. There goes my summer, I thought.

Cole, after his injury

Fortunately not so. Dr. Ingram, with the assortative mating project, took me onto his project. His team needed a boater who would row around on a pontoon in support of snorkelers who were sampling nest sites. From the boat, I could transport fish and eggs and record environmental data more easily than the snorkelers. Luckily for me, I could row without applying too much pressure on my foot or risking getting it wet. I jumped at this opportunity to help the team’s data collection efforts, which were going to help understand if stickleback in each lake mated according to similarity in diet. This was done by checking the carbon and nitrogen isotope ratios from the eggs in the clutch; which served as a proxy for the female diet, against the isotope ratio in a muscle clip taken from the male stickleback defending the nest. I spent the rest of the summer field season passing the hours on the little pontoon inflatable rowboat taking in the beautiful Canadian landscape, which like the boating, continually took my breath away.

From left to right: Yoel Stuart, Cole Thompson (the author), Andrew Doggett (a high school teacher), and Brian Lohman

Once the field season ended I continued working in the lab performing DNA extractions and morphometric analysis on the specimens collected on Vancouver Island until the end of the summer. During this time I became awed by being part of the scientific process. I was doing science. Not only had I helped collect specimens, but now I was generating data for analysis and I wanted to find out what the data said. To do that, I began volunteering in the lab after my summer contract ended. I sorted through benthic samples, took pictures of the fish we collected, used these pictures to measure differences in morphological traits, dissected out gill rakers and gut contents, examined gut contents for parasites, and transcribed ecological data. I couldn’t get enough. I wanted to learn how the environment and evolution has shaped these fish. As we sorted through the data, our preliminary data from the pictures of the fish showed that some lake stream pairs are evolving in a parallel fashion but this could be entirely antiparallel to other lake stream pairs, showing that there is clustering in directionality, but no steadfast uniformly parallel direction of evolution that holds across all watersheds. Dr. Yoel Stuart worked tirelessly on this project, and with help from Dr. Bolnick, formalized his findings on parallel evolution in the lake and stream in a Nature Evolution and Ecology in May 2017 titled Contrasting effects of environment and genetics generate a continuum of parallel evolution, showing that the environment dictated the direction of evolution, but genetics dictated the extent to which evolution occurred. My field and lab work earned me co-authorship on this paper.

Invigorated by my experiences in the lab thus far, I wanted to work in the lab again the following summer and with help from Dr. Bolnick and Dr. Stuart, was awarded an undergraduate research fellowship and an NSF-funded REU (Research Experience for Undergraduates) fellowship for summer 2014 to work on my own independent project in the Bolnick Lab. This project, examining the parallel evolution of jaw morphology and biomechanical values such as suction index, would be an extension of the work I had helped with the previous summer. For this project, I would excise the jaws of fish I had previously processed and take pictures of the jaw to calculate different metrics related to jaw function. With this I got to further embody the scientific process---creating hypotheses and synthesizing the results into a manuscript in addition to data collection, processing, and analysis I helped with the year before.

I worked, and worked, and worked on this project from summer 2014 until the November 2017 Evolution publication titled Many‐to‐one form‐to‐function mapping weakens parallel morphological evolution(Thompson et al 2017 Evolution). The results from my data collection and functional calculations showed that there is increasingly weak parallel evolution for biomechanical systems in which there are a greater number of morphological combinations that can generate the same functional output. That is, systems that are one-to-one in form and function are more parallel to each other than systems that are many-to-one in form and function, as there are multiple solutions that generate the same value. I also collaborated with a fellow undergraduate Newaz Ahmed documenting the not-so-parallel evolution of brain morphology in these stickleback (Ahmed et al 2017 Ecology and Evolution).

During this 3 year process, with lots of help from Dr. Bolnick and Dr. Yoel Stuart, I did things I never thought I could do, or would do, like using R, a statistical software, to test our data, and help write a formal manuscript for publication; which, even with lots of encouragement and help, sometimes felt like an impossible task. Even so, in parallel to this project, I filled my life with lab-related things. I helped assist two other major projects in the lab, made life-long friends in the lab, found a quiet study place in the lab, met my wife across the hall from the lab, and learned about evolution, immunology, statistics, and countless other subjects while in the lab. In short, I spent the rest of my time in undergrad in “my place” at UT: Dr. Bolnick’s lab.

Cole and Lauren got married last summer!

And now, almost 5 years since my first trip, I am thankful for the opportunity to go to Canada, do field work, and be a part of the scientific process—which to this day, has been the most influential experience of my life.

This final part of the post is a video. Cole liked to video himself when he was on the pontoon rowboat and no snorkeler needed himself. He would babble about nothing in particular. We found a bunch of these kinds of videos on our GoPro cameras after the field season. And he probably never thought these would resurface to embarrass him. Little did he know.

Tuesday, March 27, 2018

The “16 types of graduate student by JRR Tolkien” was
extremely easy to write, and the various characters Tolkien described very
nicely matched with various supervisor types. The present post on the “17 types
of graduate student by GRR Martin” was much harder to write - partly because characters
in Game of Thrones don’t match so cleanly onto student types, and also because
all the Game of Thrones characters seem fundamentally flawed. Stated another
way, most Tolkien characters are inherently good, with perhaps a few temporary
flaws; whereas most Martin characters are inherently bad, with perhaps a few
temporary redeeming qualities. Thus, please read the following not as an
attempt to describe actual graduate student types but rather to envision the
various GRR Martin characters as if they were graduate students. In truth,
graduate students have many more positive qualities than Game of Thrones characters.

The Khal Drogo

The Drogo is extremely capable in field situations,
including managing huge field crews with difficult logistics in uncompromising
environments for long periods of time. However, he isn’t very intelligent,
doesn’t publish much, and – it seems – would prefer to just stay out in the
field rather than having to deal with committees and reviewers and
administration.

The Ned Stark

This student is a zealous advocate of open science, data
sharing, pre-registration, systematic meta-analyses, data archiving, open
access, and all forms of transparency in science. He is much admired by other
students for these stances, even though they would never seek to emulate his puritanical
approach. Unfortunately, this warts-and-all approach to writing papers leads to
frequent rejections from major journals, which – curiously – only strengthens
his resolve.

The Viserys Targaryen

The Viserys is the son of a famous Professor – and he never
hesitates to remind everyone of it. He seems to think that his pedigree
entitles him to success without much effort – and he is extremely annoyed by
rejections from journals and, in fact, any form of criticism. Owing to his
obnoxious sense of entitlement, this student could well be kicked out of the
department if the Qualifying Exam or Defense committee are too irked by his
attitude.

The Jon Snow

Jon Snow’s current Professor agreed to supervise him at the
request of the Chair of the Graduate Training Committee when the Snow’s former
supervisor retired pre-maturely. His new supervisor accepted this role on
condition that the Jon Snow would fund himself and not take up space or
resources used by the other students. Despite all of these constraints, the Jon
Snow is very hard working, serious (perhaps overly so), and dedicated. He turns
out to be an exceptional, if understated, student who will start his academic
career at a tiny undergraduate college but will ultimately be recruited to an
Endowed Chair at Harvard.

The Daenerys Targaryen

For the first part of her graduate degree, she shared an
office with a Viserys and – as a result – suffered from a serious imposter
syndrome. Once the Viserys was kicked out of graduate school, however, she
really came into her own and, in fact, (re)discovered a new methodology (three
of them, in fact) that have made her one of the most influential and sought-after
graduate students for collaboration. She seems destined for a position at a
major research university, although she will face considerable challenges
imposed by jealous competitors.

The Walder Frey

This student worked for a long time in the lab of one Professor,
who advised and funded all of the research. Then, just before submission of the
paper, the Walder switched to the lab of a competitor, taking all of the data
with him and dropping his original supervisor from all the papers.

The Tyrion Lannister

Supremely intelligent, the Tyrion sometimes seems to
squander his abilities and talents in food, drink (lots of it), and various
social activities. This joie de vivre is somewhat understandable as his
previous supervisor was mean and condescending, never giving the Tyrion credit
for any of his discoveries. With a more understanding and appreciative
supervisor, however, the Tyrion will cut back on his socializing (if not his
drinking) and generate extremely novel and inspiring ideas.

The Littlefinger

From day one (and probably well before that), this student
has been relentlessly maneuvering everything and everyone in an effort to
maximize his career advancement. He is extremely effective at twisting any
given collaboration to his favor, such that he now has a very good publication
record. However, as time as gone on, his manipulative tendencies have become
more widely known and he runs the risk of being blacklisted by the academic
community.

The Cersei Lannister

Deceptively clever, the Cersei is rising quickly within her
field, collaborating with important people (although they don’t always seem
better off for it) and publishing many papers (although some say the work isn’t
really hers). Rumor has it that much of her success comes from stealing the ideas
of other students and undermining the success of her colleagues by providing
withering reviews of their papers and grant applications.

The Tywin Lannister

The Tywin has published many excellent papers and intends to
keep doing so. He is smarter than most (perhaps all) of the people around him –
and he knows it. He has a hard time concealing his contempt for others, even
his supervisors. He will go far in academia – but no one will like him.

The Brienne (of Tarth)

Highly skilled and loyal (almost to a fault), the Brienne
will do whatever her supervisor asks of her, quickly and efficiently, without
any complaint whatsoever. It isn’t clear that she has the independence to run
her own research program, but she is very good at improving the research of
those around her. At the same time, her intensity and dedication to principles
can sometimes off-put those around her.

The Brandon Stark

The Bran seems to think on another plane. It isn’t so much a
book-smart type of intelligence but rather a more intuitive, gut-feeling
approach to academic topics – or so it seems. When he asks questions in seminars,
no one can understand them – but it is nevertheless clear they are extremely
insightful. He sometimes seems to know the outcome of an experiment even before
it starts and he has an amazing recall for past details of scientific studies –
even unpublished ones in which he wasn’t involved. He will only publish once –
but it will likely win him the Nobel Prize.

The Jaime Lannister

When the Jaime was a senior graduate student, he blew the
whistle on misconduct by his supervisor, who was then censured by the university
and has disappeared from academia. Although some laud the Jaime’s action in
this case, other supervisors have been reluctant to take him on. As a result,
he is a quite jaded and often makes acerbic comments about the whole process of
graduate school. Deep down, however, he just wants to do good science –
although he has some pretty weird relationships with other students.

The Robert Baratheon

You have never met a person who enjoys living quite so much
as the Robert. He is the life of every party and this popularity has carried
forward to many collaborations and supporters, generating some outstanding
papers. It seems, however, that his hard-living ways might be getting the most
of him and he could flame out soon.

The Arya Stark

The Arya applied for a series of international fellowships and has been away for much of her degree. On her return, she is much more mature and experienced, having picked up a set of extremely rare and exceptional research skills, although it isn't clear she always uses them for the best purposes.

The Davos Seaworth

This student came from nowhere and, through simple hard work
and dedication, has risen to a place of influence within his field. He has
exceptionally good advice for other students in the lab and will – occasionally
– directly disobey the wishes of his supervisor. Yet, whenever, he does so, it
seems he made the right decision after all. He is extremely humble, almost
annoying so, and would probably turn down an academic position on the excuse
that he isn’t really worthy.

The Sandor Clegane

Another very capable student, he suffers one major flaw – he
is terrified of snakes, even though his research is conducted in tropical
environments abounding in them. Ok, perhaps he suffers several flaws, another
one being his taciturn and blunt criticism of ideas he deems uninteresting and
experimental designs he considers flawed. It seems clear that, deep down, he
would really like to be a Professor and has the skills to do so; yet his
difficult personality might preclude this.

Thursday, March 15, 2018

Extremely wise – if sometimes inscrutably so – and able to
solve your biggest problems, the Gandalf is often absent for long periods of
time. And these can often be the most inconvenient times for him to be away. In
his defense, these absences are often for extremely important meetings or to deal
with problems in his collaborative network. Don’t count on the Gandalf for much
day-to-day help with minor tasks but, catch him at the pub, and he will be fun
and a fount of wisdom.

The Boromir

He is very good at solving your day-to-day problems, yet he does
so reluctantly and seemingly without enjoyment. He is very skeptical of your
ideas and will only let you pursue them when your committee guilts him into it.
Often brooding, you get the impression that the Boromir might not like you. Indeed,
he might be stealing your ideas and publishing them separately – although he
will feel extremely guilty about it.

The Faramir

The Faramir had a famous PhD supervisor who is still active, and he has a bit of
an inferiority complex about it. He is very sincere and helpful but often tries
to adhere to the ways of his previous supervisor, even though they don’t really
work that well for his own students. Fortunately, a well reasoned argument can
usually shift the Faramir around to your way of thinking.

The Galadriel

The Galadriel is a giant in her research field and, if you
are hard working and enthusiastic, she will provide you with tons of resources
and moral support. She designs and constructs her own laboratory and field equipment,
which is exceptional. However, she doesn’t travel much owing to a dependent
husband, and so you are on your own in the field and at conferences.

Also,
very occasionally, she has this intense look that is very intimidating.

The Saruman

Long past the normal retirement date and having won the most prestigious prizes
in his field, the Saruman is not satisfied and wants more fame. He will take a
lot of graduate students but will ruthlessly use them to advance his own career
and fame. He has a huge lab but will make you work long hours in poor conditions, and yet still try
to make you feel like he is doing you a favor.

The Denethor

Nearing retirement, the Denethor is at a famous university
but is perceived as one of the lesser lights there. He knows people think this
of him but won’t accept it and so routinely lashes out at his students and
denigrates them as a way of feeling better about himself. He has a huge lab
with tons of money, but he is constantly afraid that the university is trying
to take it away from him. Don’t expect much understanding from this type of
supervisor.

The Eowyn

A brilliant scientist, she doesn’t get the recognition she
deserves. Yet she forges ahead in her research, publishing excellent papers
that, sadly, don’t tend to get accepted at the best journals. She is a bit
jaded now and, while supportive, seems not to pay much close attention to your
project. All her focus is on that elusive first paper in Science.

The Samwise Gamgee

Working at a small liberal arts college, the Gamgee is the
ultimate micro-manager, always looking over your shoulder offering help and advice.
He has a good understanding of basic lab and statistical procedures but doesn’t
seem to have many truly original ideas. Yet the Gamgee is always there for you,
offering what (little) funding he has and supporting you in your success and
your failures. You sometimes get the feeling that he has come to think of your success
as his crowning career achievement.

The Aragorn

Quiet and reserved, this supervisor is the ultimate skill-master.
If you need to analyze your data, he can write the scripts. If you need to find
that rare species, he is the only one who can do it. He doesn’t publish very much,
but the few papers he does publish are very good – so good in fact that they
could probably all be in Science. However, he really doesn’t want the hassle
and so usually submits to much lower journals – unless encouraged (pestered
almost) repeatedly by his colleagues to shoot higher. Unfortunately, the
Aragorn doesn’t seem to enjoy his job very much and would probably rather be
off somewhere hiking or climbing mountains.

The Pippen

Like the Gandalf, the Pippen is often absent but, unlike the
Gandalf, not for work-related purposes. He is usually surfing or fishing or
just hanging out somewhere. He sure is fun though, especially when hanging out with his prof buddy from down the hall. Great lab parties, with tons
of food and drink and lots of laughter and activities, some scripted and some
impromptu. He really wants to be your buddy is constantly trying to get you to
smoke weed with him. Unfortunately, the Pippen doesn’t really have any skills to
impart and essentially never publishes. Don’t choose this advisor if you hope
for a career in academia.

The Radagast

This supervisor is extremely absent minded and really doesn’t
pay much attention to you, yet it is hard not to be inspired by his sheer enthusiasm
for the world around him. You will be his only student – and, much of the time,
he won’t even realize it.

The Sauron

His lab is dark and dirty, and it smells bad all the time.
He is in constant conflict with pretty much every other person in his field. You
would think no one would be in his lab, but he is so powerful and influential that
many flock to work with him – although they don’t seem to be very happy about
it. When visiting during your recruitment, he won’t let you talk to his
students (save this one really weird guy), nor will he meet with you except by
Skype – with the video turned off.

The Elrond

This guy has been around for ages and knows EVERYBODY, often initiating huge collaborative projects. He
can really hook you up with the best and brightest people, whose respect he
commands. But, having done so, he has seemingly impossible expectations for your project. He is quite aloof and rarely travels but, just when your need is
direst, he can show up unexpectedly with a critical influx of cash or
equipment.

The Theoden

Early in his career, the Theoden had some very influential
papers – but his fame and fortune have faded owing to vindictive competitors in
his field. Fortunately, you could be just the person to rejuvenate his career
if you have the patience and self-motivation. If you can shake him out of his
lethargy, he will invest all his resources in you and plan to finish his career
in a last blaze of glory, thus resuscitating his career and showing he wasn’t a
one-hit wonder.

The Grima

This advisor has risen to a place of influence not because
of any concrete scientific skills but rather because he has a knack for flattering
the right people. He is a real creep and seems to have all sorts of unsavory designs
on his students. He might even be faking the data in the few papers he has
published, which – to everyone’s surprise – are sometimes in very good
journals.

The Smaug

He has tons of money but is extremely stingy about it. He expects
you to obtain your own funding for everything and then he takes most of it from
you. No students have successfully graduated from his lab, yet his arrogance
could be his downfall.

When I walked out of my last exam in my final year of
university, 1991 at the University of Victoria, I cold-called my intended PhD
supervisor, Tom Quinn. I gave a long, reasonably well-prepared spiel about my
passion for salmon and my desire to do graduate work in his lab. A modest
silence followed my monologue and then a “Well, it sounds like you would make
an excellent graduate student but, unfortunately, you missed the application
deadline by 6 months.” Momentarily crushed, my enthusiasm recovered when he
suggested that I come work for him over the fall. Thus began a 7-year stint with
Tom at the School of Fisheries; starting with a fall working on chum salmon at
Kennedy Creek in Washington, then a winter working with sockeye salmon fry exiting
the Cedar River in Seattle, then a summer in Alaska working with the Fisheries
Research Institute (FRI - of the School of Fisheries) camps Wood River – at that time lead by Don Rogers as well as at Lake Nerka and Iliamna Lake. FRI has now morphed into the Alaska Salmon Program.

Me in 1992 at Iliamna, Alaska.

The next year I met the deadline for application to graduate
school, applying at the same time for a graduate scholarship from the Natural Sciences
and Engineering Research Council of Canada (NSERC). In the spring, I received a
letter from NSERC denying me the option of taking my MSc scholarship to Washington
University on the grounds that it didn’t have a very good fisheries program. I
wrote back politely – but without much hope – to first agree with NSERC that
Washington University indeed was not well known for its fisheries program but
that the University of Washington was – and that it was the latter at which I wished
to pursue my studies. All was well regardless as I received an H. Mason Keeler scholarship
that enabled Tom to take me as a student and, a few months letter, I received a
letter from NSERC saying, effectively, “Oops, sorry, our mistake. Here is your
scholarship.”

Having just had a formative and inspiring set of field experiences
in Washington and Alaska, I suggested to Tom that I do my MSc on topics similar
to those the projects on which I had been working. Tom, as always, listened
politely and then suggested I instead work on rapid evolution in Lake
Washington sockeye salmon that were introduced earlier in the century. This suggestion
turned out to be exceptional as it started my path to being one of the
forerunners – along with my office-mate Mike Kinnison – in the study of rapid
evolution. At the same time, I met the great – and ever enthusiastic – Fred Utter who helped me do my first genetic work with allozymes – and still, sadly,
my only hands-on genetic work. Of course, all was not always smooth sailing,
especially when the boat – the Nettie H – I had worked on for the FRI test
fishery in Bristol Bay, sank a few months later while crab fishing, causing the
death of all on board, including Blake Grinstein, the Captain for my two years working
on the test fishery.

Blake Grinstein surveying the test fishery catch.

Having had my MSc project suggested to me by my supervisor,
I decided I needed to do a PhD all my own. I therefore suggested to Tom a
project at Pick Creek, Alaska, on the reproductive energetics of Pacific salmon.
Then followed two extremely intensive summers of field work at the Lake Nerka
camp, not only conducting research but also having a wonderful time
experiencing – and photographing – nature. 1995 was particularly memorable for probably
50 bear encounters, most of them pleasant and inspiring but some of them rather
scary. I continued to work at Lake Nerka until 2000, even after graduating,
making it an even 10 summers of Alaska work with FRI. These years included the
first research visits to Lake Nerka of Ray Hilborn and Daniel Schindler, both
of whom still work there, as well as visits by crazy drunk Soviet fisheries
biologists and crazy drunk Norwegian fisheries biologists.

The Lake Nerka camp, early 1990s.

The School of Fisheries at the University of Washington, now
the School of Aquatic and Fishery Sciences, was an outstanding experience for
me. I am especially appreciative of my supervisor Tom Quinn, who gave me some
great ideas, who shaped my manic approach to manuscript editing, who encouraged
me to explore collaborations with others independent of him, and who had a
knack for filling his lab with an exceptionally synergistic and energetic group
of students. Especially formative for me was having my desk directly beside
Mike Kinnison, now a Professor at the University of Maine, for 7 years. Although
we played Doom and then Doom II with a serial cable linking our computers between 10
pm and 1 am, we actually did research for at least as many hours before that.

While I worked on "rapid" evolution in Lake Washington sockeye,
Mike Kinnison worked on "rapid" evolution in New Zealand
chinook salmon. He helped me. I helped him. I got the better deal!

Thursday, February 15, 2018

Evolution is often portrayed
as a descriptive science, rather than a predictive one. Nonetheless, time
series data on ‘evolution in action’ can be used to quantify the predictability
of evolution. In this week’s issue of the journal Science we published an analysis of the predictability of evolution
in the stick insect Timema cristinae (Figure
1), using a 25-year longitudinal study of morph frequencies, experiments, and
genomic analyses.

Figure 1. The focal species (T. cristinae) used to study the
predictability of evolution. Credit: Moritz Muschick.

We find that the evolution of
both color morph (green versus melanistic individuals) and pattern morph
(striped versus unstriped individuals) frequencies is strongly influenced by
selection, yet the two traits differ in the predictability of their evolutionary
dynamics. Color morph frequencies are only modestly predictable through time, because
they are driven by multi-faceted and complex selective regimes that are still
poorly understood. In contrast, pattern morph evolution is highly predictable,
being driven by a more understood process that causes consistent up and down fluctuations
in morph frequency, namely, negative-frequency dependent selection. Thus, evolution
might often be as predictable as the types of mechanisms driving it, and our
understanding of these mechanisms – good understanding of natural history and
selective environments can lead to greater predictability.

In this post, I’ll offer a
brief historical perspective on the making of the study (rather than give a
detailed account of our paper, for which I direct interested readers to the
article itself). My own interest in the predictability of evolution dates back
to when I was a graduate student, and read the now classic 2002 paper in Science by Peter and Rosemary Grant
about unpredictable evolution in Darwin’s finches. It struck me then that the
real problem here was predicting the weather, because if that could be done
then subsequent effects on seed size distributions and the evolution of finch
beaks might be predicted. My interest in limits on predictability was peaked,
but I had to wait two decades to accrue the date required to publish on it (in
terms of a temporal context like the finch study).

Figure 2. Collecting stick
insects. Credit: Moritz Muschick.

From the years 2000 to 2017
inclusive I collated data on morph frequencies in T. cristinae in the hills around Santa Barbara, California (Figures
2 and 3), and Cristina Sandoval (who introduced me to the system) contributed
data from the 1990s. I proofed the data and centralized it into a master database
over a recent summer. When asked why I was doing this, my reply was ‘I don’t
know, something will emerge’. Patterns consistent with the conclusions above
emerged from the time series data. This was interesting, but not sufficient to
establish causality. We thus used genomic analyses to bolster the evidence for
selection, and experiments to test for sources of selection, such as
negative-frequency dependent selection. The story was coming into place, but we
still did not have the focus required to write a compelling paper. After reading
Jonathan Weiner’s book ‘the Beak of the Finch’ and having pub discussions
concerning the role of deterministic versus random events in evolution, we were
finally ready.

The manuscript was then
written, many years after the seed of interest was sown. It’s now published,
and we conclude that our
constrained understanding of selection and environmental variation (i.e.,
limits on data and analysis), rather than inherent randomness, can limit ability
to predict evolution. In terms of eco-evolutionary dynamics, these limitations
may affect our understanding of ecological processes, because to the extent
that evolution can be predicted, perhaps so can its consequences for population
dynamics, community structure, and ecosystem functioning. In T. cristinae specifically, changes in
morph frequency affect bird predation, which in turn can affect entire
arthropod communities and plant herbivory (e.g., Farkas et al. 2013 Current Biology). Thus, limits to
predicting evolution within species may be data based, with far reaching
consequences for interacting species.

Monday, February 12, 2018

I just got back from a trip to Dalhousie University,
to which I was invited by grad students to speak in the Department of Biology. Among
the many interesting conversations was one I had in which Gaia and cancer
somehow came together. My host, Sarah Salisbury,
and I were speaking with Dr. Ford
Doolittle and Andrew
Inkpen, about their ideas on how natural selection might act at the level
of processes – as opposed to the “things” that generate those processes. I won’t
spill the details as they will be outlined in a forthcoming paper of theirs. However,
I did want to relate how we got from Gaia to cancer and, then, during the course
of writing this post how I ended up at the holobiont. (Get ready for a lot of “scare
quotes” as I try to extend terminology in each of these areas to the others.)

Dalhousie is 200 years old - how cool is that.

According to Wikipedia, the Gaia hypothesis “proposes that living organisms interact
with their inorganic surroundings on Earth to form a synergistic and self-regulating, complex system that helps to maintain and perpetuate the
conditions for life on the
planet.” One way of framing this hypothesis is that global ecology and
the evolution of life feedback to one another in such as way as to facilitate
and maintain life on earth. Taken to extremes, one could say that natural
selection favors the self-regulating feedback itself as life would otherwise cease
to exist – but how would we ever test this hypothesis?

In group selection or “higher-level selection” arguments
of this sort, one would normally need multiple entities with heritable traits
influencing differential “survival” and “reproductive success”. In the case of
Gaia, then, we would need life originating on multiple planets among which
selection was then occurring – because it is impossible to have selection among
things if you only have one thing. Of course, one might argue that selection
has indeed acted in this way and that our planet (or others we can’t perceive) is
the only one left – because life did not evolve synergistic self-regulation on other
planets and therefore went extinct. Or one might argue that selection on our
Earth has weeded out organisms that do not participate well in this synergistic
self-regulating system. Any of these speculations could well be true, but it is
impossible to study such processes in the real world because we only have the one
world.

Or do we really only have one world? As we were
discussing Gaia, I started to think that perhaps we could use cancer as a Gaia
model. Consider the similarities. Cancer starts with a single cell than then
proliferates into a great diversity of descendent cells; much as current life
on Earth has proliferated and diversified from a single initial cell. Then, the
cancer that proliferates on an individual “host” organism will (in most cancers)
leave no descendants when that organism dies; just as we might expect that (barring
colonization of new planets) life on earth will cease to exist when the Sun has
run its course. In addition, cancer can kill its host and be the reason for its
own extinction, as well as most other life occupying that host; just as some
life – us perhaps –could severely damage the Earth and kill much of the life on
it. Thus, perhaps we can view cancer as a lineage of organisms proliferating on
its own finite planet that, should the cancer disrupt the synergistic self-regulation
of that planet, the cancer itself and much of the life on that planet will cease
to exist. Considered in this way, perhaps we can – at least for the sake of
argument – speculate on how cancer and its proliferation in
individual hosts might yield insights into the Gaia hypothesis.

An awesome book on cancer.

When I started this post, I was thinking that much of
the analogy from cancer would seem to parallel ideas supporting the Gaia hypothesis:
for instance, “nicer” (as opposed to “meaner”) cancers should leave the host
alive longer, nicer cancers should enable the persistence of more life on the
host for longer, and so on. Indeed, all of these things are true. However, it now
seems to me that one fact runs directly counter to the Gaia hypothesis: cancer
exists, is common, and routinely kills its host. This fact might be taken to mean
that selection does not generally favor a synergistic self-regulating system in
the context of cancer and its “planet”. Why might this be? I speculate it is
because cancer (the non-heritable kinds) are never transmitted to other hosts –
that is, to other “planets.” In this case, selection would never favor cancer being
nice to its host because, no matter how long the host lived, the cancer would
never be passed on: as opposed to infectious/transmittable diseases of hosts
where selection can indeed favor reduced virulence. For this reason of non-transmissibility among hosts/planets, presumably selection cannot act among the cancer/life on
different hosts/planets to favor synergistic self-regulating systems on those
hosts/planets.

Ok, wait, you might say, cancer is actually nice to
its host because it rarely strikes before reproduction: however, the reason here
isn’t selection on the cancer but rather selection on the against alleles in
the host genome that increase the chances of pre-reproductive cancers. That is,
it isn’t selection on the inhabitants of the hosts that favors synergistic self-regulation,
rather it is selection on the host itself. Unlike hosts, however, planets do
not have genomes that can be selected to “punish” lineages (species) that are
not nice to the overall system. Or is that true? What if we consider all life
on the planet as its genome – in this case, the “genome” of a planet perhaps
could be selected to eliminate parts of that genome that do not promote
self-regulation. That is, life could self-police itself through elimination of
non-cooperative life. Interestingly, even this analogy could perhaps be extended
to the cancer scenario: all the genes in a host, including all genes in all
species living on or in that host (the so-called “hologenome” or “holobiont”),
could be selected to act against cancers that are detrimental to the host itself.

I am not sure if any
of this is useful in anyway, but it sure is interesting – to me at least. I
have no intention of actually studying or testing these ideas in any way, but I
have certainly been interested in the evolution of cancer for some time. For
instance, here is a previous post in which I speculated about the fundamentally
different problem posed by cancer relative to other forms of life that are
detrimental to humans. In addition, I have recently become very interested in
the microbiome (a key part of the holobiont) as regulator of fitness and
adaptation. Indeed, just today, my student Lotte Skovmand, had her qualifying
exam, which she passed (Congratulations Lotte!), in which she will examine the
drivers of microbiomes in plants and howler monkeys. Perhaps that is how I got from
Gaia and cancer last week all the way – today – to holobionts. Nothing like colleagues
and students to get you thinking about new things!